She’s known for playing some of the more memorable airheaded blondes commited to celluloid in “Mighty Aphrodite” and “Romy and Michele’s High School Reunion,” but Academy Award-winner Mira Sorvino is no dummy. Since winning an Oscar for her career-making turn as a daft prostitute in Woody Allen’s “Mighty Aphrodite,” the Harvard Univeristy graduate (she majored in East Asian Studies magna cum laude) has built an impressive body of work by juggling indie work with studio fare, all while giving birth to four kids and serving as the United Nation’s Goodwill Ambassador for human trafficking since 2009.

In her latest indie vehicle to hit theaters, “Union Square” (opening this Friday), Sorvino plays Lucy, a manic mess of a woman who surprises her estranged sister Jenny (Tammy Blanchard) by showing up unannounced at her glam New York apartment overlooking the New York location of the title on Thanksgiving eve. Over the course of two days, Lucy and Jenny lay their grudges bare, reveal some big secrets, and make an effort to get along once and for all.

A glowing and chatty Sorvino caught up with Indiewire in Manhattan to discuss what she describes as “one of the best movies” she’s done in a “very long time”; her relationship to her father, veteran character actor Paul Sorvino; her refusal to play the villain; and that Oscar win.

Lucy is the definition of a hot mess in “Union Square.” It must have taken so much out of you to play her.

It did — although it was very fun and freeing. It’s electrifying to get to play someone who’s able to do whatever she feels. That being said, you had to feel whatever she felt. It felt so extreme all the time because she’s struggling with bipolar disorder. The funny thing is, in the beginning of the movie you just think she’s hysterical, not knowing if you can take much more of her. But once you get into it, then you see her more delightful side. She can be bubbly, ebullient and funny, but then she crashes into these moments of sadness. But, you come to realize, it’s for a good reason.

It was hard to play the heavy side of it. The scene along the river [where she contemplates suicide] killed me. The thing was, we had a short window of time to do the scene because the sun was coming up. We did it at four, five and six am. Every minute of that was too long for me, because it was so upsetting to play. But I was lucky to get the role. It’s a fantastic one.

How do you get your energy level up to where it needs to be to play a character as charged as Lucy?

A lot comes the personality of the character. Once you find that, it just drives you around. I do work off of caffeine a lot. I’m a sort of coffee addict. And protein bars. Every few hours I’d have one and a latte from Starbucks [during our interview, Sorvino sipped from a Venti Starbucks latte].

Did the rushed shooting schedule help you in that respect?

Yes, it helped because you had the adrenaline of a race. You had to start it and you had to finish it. You couldn’t just decide, “Today I want to shoot five pages rather than ten.” If it had been longer, it would have been very hard for me. Nobody was doing it for money. There was no money in it. You could say that I paid to be in it, because I had to pay my nanny twice my daily salary to work on it [laughs].

But I think it’s one of the best movies I’ve done in a very long time. It’s rare to find something that’s a dramedy like this. Usually it’s only comedy or drama. And a lot of independent films, it’s usually heavy drama. As a viewer these days, I don’t want to choose something that’s going to bring me down, but I don’t want to see something that’s stupid either.

Do you know anybody like Lucy?

Yes, and I’m not at liberty to say who. She’s parts of that person in terms of the way the bipolarity expresses itself — the fun and juvenile [aspects] of her personality. But there are other parts of the character that are unique to her. If I had not had that person to draw from, it would have been a very different portrayal.

You’ve stuck to mainly indies over the course of your career. The few studio dips you have made were for the most part with auteur types like Guillermo del Toro (“Mimic”) and Spike Lee (“Summer of Sam”). Since winning the Oscar, did you set out to only do work that really spoke to you as an artist?

Yeah, that’s always been my way. I think it’s commercially that hurt me. But I never had this strategy to stay on top, or be as marketable as possible. When I was a kid and wanted to be an actor, I used to think, “Gosh, I’d like to do great roles, but have no one in my real life know who I was.” I wanted to enjoy anonymity. I’m a private person.

Did growing up with your famous father influence that wish?

Yes. People would always come up to us, and he would have to sign autographs… at restaurants, airports and stuff. I was always shy. It just made me nervous. Other people love that and that’s what they want. They have that life of the party personality. So in an odd way, I’ve got to play great roles, but I’m not nearly as famous as some of my contemporaries. That’s worked for me in my personal life.

Right now, with my four kids and my marriage, I love them so much and I’m happy to not be constantly barraged with attention. It’s interesting, how everything’s turned out — not to say that I don’t want commercial success, or don’t want to make big movies that are powerful.

Also, being pregnant four times has taken me out of the market for a few chunks of time [laughs]. But I also think that in indies, you have the chance to achieve something that is pure, and this is the perfect example of that.

Despite having four kids, you’re remained remarkably busy on the film front.

I still love working. I love doing what I do, but I try to do shorter projects now. But I don’t want to retire! You do a few projects a year, you pick interesting roles, so it works out. You can’t only do ones the size of this film, because you can’t survive financially. Right now the business is very difficult for actors, very difficult. A lot of actors have to go back to their day jobs in order to get paid for their acting. Obviously I have to mix it with jobs that have financial salaries.

I did this movie that comes out in September that stars Dermot Mulroney that’s about the slave trade of children in Cambodia. Because I work as the Goodwill Ambassador after making “Human Trafficking,” it was a great way to marry activism and artistry. On that one I took the children. It was a great experience for them. They got to ride all these boats on these rivers and meet the kids. It was so eye-opening for them to get to travel. I remember when I travelled with my dad on location, how interesting that was.

You just balance. There are negatives to working away from home, but it also broadens your kids’ world so much.

It’s always a hard push because my dad and my mother made the decision, once I was in second grade, that my mom would stay in Jersey with us at home while he worked during the school year. So we did not follow him around, except in the summertime. Before that we had gone to the Bahamas, Spain, England… I think it eventually broke up their marriage. So much time apart separated them. I don’t want that to happen to us, so I do bring the kids along more than some people.

Your father initially wasn’t thrilled about the idea of you entering the industry, correct?

Well, I got bitten early by doing school plays. I did a play in third grade called “The Mystery of the Missing Capitalizations of Punctuations” [laughs]. I played a teacher with a silly voice and a big wig. Fifth grade, I did another play, and that’s when my dad started to teach me about substituion. My dad was my [acting] coach when I was a kid. Then doing these performances in front of an audience gave me a rush like downhill skiing. You never knew what was going to happen next. This movie has that same feeling — I didn’t know what was going to happen next with Lucy.

The roles that you’re best known for — Linda Ash in “Aphrodite” and Romy — are so endearing because they seem so unaware of how folks perceive them. They’re not the brightest bulbs, but they don’t seem to know it or care. What attracts to you to those types of characters? Are people surprised when they meet the real you?

I think they used to be more surprised. Now people have to some extent through media gotten to know my essential personality. Also, people always stress that I went to Harvard, so they assume that I can’t be all that dumb. There is a thread of continuity in those roles. But in this one, the character is actually smart. She’s just emotionally all over the map. She looks like a dumb blonde, but she’s actually not dumb.

I have a hard time playing people that I don’t like. I haven’t played many villains. I think very early on I played a femme fatale in a short film that got me the Robert Redford movie. But that was one of the only times I played a morally corrupt character. Oh, and in “Barcelona” too.

That’s the film that got you the Woody part.

Yeah, you’re right. Whit [Stillman] screened it for Woody. The casting director had read me once and thought it was too far away from my natural personality. But to get back to why I’m drawn to these roles — one is the heart, two is the unfettered quality (maybe because in my life I am not unfettered, I get anxiety about how I said something).

About your Oscar win — how’s it been living with that title over your head?

Well they don’t give you a tiara and scepter. You got this beautiful and wonderful honor. It’s definitely a great addition to my life, but I don’t wake thinking, “I’m an Academy Award winner.” I just remember it as this incredible, pivotal moment for me. It took the pressure off my career in a way, even though people would probably think it’s the opposite.

Many people go their entire career — great actors — never being nominated or never winning. I had this incredible gift given to me at a young age, so I felt validated and appreciated early. I’m not a greedy person. It’s not like, “Okay, where’s the next?!”